frommelt etal



March 17, 1964 FRQMMELT ETAL 3,124,864

REPLACEABLY MOUNTED INSERT Filed Oct. 5, 1960 3 Sheets-Sheet l INVENTORSHORACE A. FROMMELT BY 4 RT E-WATLING AH-orncys March 1964 H. A. FROMMELTETAL 3,124,364

REPLACEABLY MOUNTED INSERT Filed 001;. 5, 1960 5 Sheets-Sheet 2 ilillINVENTOR. HORACE A. FROMMELT y 4 ROBERT EWATuNe Amrncys March 1964 H. A.FROMMELT ETAL 3,124,364

REPLACEABLY MOUNTED INSERT 5 Sheets-Sheet 3 Filed Oct. 5, 1960 Fig. 13.

INVENTOR. Homes A. FROMMELT Fig. 12.

AHomeys United States Patent 3,124,864 REPLAQEABLY MOUNTED INSERT HarareA. Frommelt, Philadelphia, Pa, and Robert E. Wading, Salem, ind,assignors to Fer-r0 Powdered Metals, inc, Salem, End, a corporation ofIndiana Filed Oct. 5, 1969, Ser. No. 60,653 1 Claim. (Cl. 29-%) Thepresent invention relates to improvements in tool holders and finds animportant utility in the mounting of hard bits in cut-off tools, partingtools or single point cutting tools.

Cut-off tool or parting tool are terms used by those skilled in thepresent art to designate tools used for cutting oif portions ofcomponent materials such as bars having circular, square :or hexagonalcross-section. The term single point cutting tool designates a cutterused in lathes, planers, shapers, vertical boring mills and similar suchdevices. it is the practice to provide such cut-ofi tools and singlepoint cutting tools with bits formed from hard elements such as tungstencarbide, titanium carbide, high speed steel, ceramics, etc.

Because of the extremely brittle nature of carbide and ceramic bits,surface irregularities on such bits promote their fracture. Thus,present practice is to grind these bits down, in order to minimize thedanger of breakage if clamping is to be employed for holding the bit, orto provide a satisfactory brazing surface if brazing is to be employed.This time consuming grinding or abrading operation adds substantially tothe cost of the tool. It is estimated that the grinding operationincreases the cost of using the average bit by a factor of about twicethe cost of the raw bit.

Since the cost of ground carbide bits was heretofore a substantial costfactor in finished cutting tools, it was deemed necessary to resurfacethe bits when they become dull in order to prolong their usefulness.This meant removing the bits from the cutting tool holders or bodies,resurfacing with an expensive diamond grinding operation and thenrealigning and readjusting the bits in their mounts. Thus, the cost ofusing the tools included not only the initial high cost, but also thecost of substantial refinishing operations necessary throughout theuseful life of the tool.

These problems and others relating to the mounting of hard bits havebeen partially solved by the invention of Horace A. Frommelt (one of thepresent inventors) and Fred Aberlin as described in U.S. Patentapplication, Serial Number 585,039, entitled Cutting Tool and Method ofMaking, filed May 15, 1956, now Patent No. 2,950,523, this inventionproviding ways for inexpensively firmly fixing hard bits in supportingelements formed from powdered metal. Thus, such hard bits mounted in powdered metal supports because of low cost, may be used until the cuttingedge or operating surface is worn out and then the support with bitthereon thrown away.

It is, therefore, an important object of the present invention toprovide an improved tool holder permitting quick and accurate fixing ofa powdered metal, bit-carrying insert in correct operating position andpermitting quick and accurate replacement of such bit carrying inserts.

A funther object of the invention is to provide an improved tool holdercapable of use with any type of cutting or wearing tool whether portionsthereof be formed of powdered metal or otherwise.

Still another object of the invention is to provide an improved holderfor use in a cut-off tool or in a single point cutting tool.

Related objects and advantages will become apparent as the descriptionproceeds.

In accordance with the present invention, there is provided a toolholder comprising a shank having a recess,

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a tool carrying insert received in said recess, means for repeatedlypositioning said insert in said recess in the same position, and meansfor clamping said insert in said position.

The full nature of the invention will be understood from theaccompanying drawings and the following description and claims:

FIG. 1 is a side elevation of a single point cutting tool or turningtool embodying the present invention.

FIG. 2 is a top plan view of the cutting tool of FIG. 1.

FIG. 3 is an end elevation of the cutting tool.

FIG. 3A is a plan view of one of the components of the tool of FIGS.1-3.

FIG. 4 is a side elevation of a cut-off tool embodying the presentinvention.

FIG. 5 is a top plan view of the cut-off tool of FIG. 4.

FIG. 6 is an end elevation of the cut-off tool.

FIG. 7 is a side elevation of an alternative embodiment of the cut-offtool.

FIG. 8 is an end elevation of the cut-off tool of FIG. 7.

FIG. 9 is a side elevation of a further alternative embodiment of thecut-off tool.

FIG. 10 is an end elevation of the cut-01f tool of FIG. 9.

FIG. 11 is a side elevation of an alternative embodiment of the singlepoint cutting tool or turning tool.

FIG. 12 is a top plan View of the cutting tool of FIG. 11.

FIG. 13 is an end elevation of the cutting tool of FIG. 11.

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawing and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, such alterations and furthermodifications in the illustrated devices, and such further applicationsof the principles of the invention as illustrated therein beingcontemplated as would normally occur to one skilled in the art to whichthe invention relates.

Referring now more particularly to the drawings, there is illustrated inFIGS. 13A a single point tool or turning tool it) including a shank ll.which has a generally rectangular, elongated shape and preferably isformed of powdered metal. The shank i1 is formed at its distal end andparticularly in one corner thereof with a rectangular recess 12 whichreceives a bit carrying insert l5, said insert being formed preferablyof powdered metal and the bit is carried thereby being formed ofcarbide, ceramics, high speed steel, stellite, diamond or any otherdesired hard composition. Preferably, the bit 16 is fixedly securedwithin the insert 15 in the manner described in the above mentionedcopending application.

Formed upon the upper surface of t e shank 11 contiguous the recess 12is a plurality of serrations 17, the various surfaces 13 of which meetadjacent surfaces 18 at degree angles. The serrations l7 cooperate withmating serrations 2t in the lower surface of a clamping element 21 tosecurely position the clamping element with respect to the shank it.

The clamping element 21 has an arched shape, a portion of one foot 22 ofwhich overlies the recess 12 whereby the one foot with its serrationsengages the insert 15 securing it in place. It can be appreciated thatthe three walls 12A, 12B and 12C of the recess 12 may be used for aninitial positioning of the insert 15. After such initial positioning,the clamp 21 may be forced against the insert 15 by tightening down of afastener 25 causing the clamp to resiliently deform at its centralarched portion and causing the foot 22 to securely retain the insert 15firmly seated within the recess. The fastener 25, which is aconventional cap screw having a hexagonal recess in its head for therotation thereof, is threadedly received within a suitable threaded bore26 in the shank ill.

It can be appreciated that, when it is desired to replace thebit-carrying insert because of wear, all that is necessary is theioosening or partial unthreading of the fastener so that the clamp mayeither be turned 90 degrees from its illustrated position or drawn awayfrom the insert so that it may be removed. The elongated,fastener-receiving slot 24- in the clamp 21 facilitates the moving ofthe clamp away from recess 12 and also permits desired positioning ofthe clamp. It should be noted that the clamp 21 is provided with a chipbreaker 27 which is fixed to the clamp adjacent the bit 16 and whichfunctions to break chips produced by the turning operation.

Referring now to FIGS. 4-6, there is illustrated an even more effectivedevice for accurately clamping a replaceable bit-carrying insert inposition. This alternative embodiment comprises an elongated slendershank 30 formed from powdered metal and having a recess 31 in one endthereof, the recess 31 having two perpendicular faces 31A and 318.Received within the recess 31 is a bit-carrying insert 32 preferablyformed of powdered metal and having perpendicular faces corresponding tothe faces 31A and 31 Extending from the perpendicular faces of theinsert 3?. is a continuous ridge 35 which is received within anindentation 36 in the shank 30, the indentation 36 being formed in thefaces 31A and 31B. It can be appreciated that when the insert 32. is inthe recess 31, the ridge 35 and indentation 36 will cooperate toprecisely position the insert within the recess. Thus, since eachreplacement for the insert 32 has an identical shape to insert 32, itwill be precisely positioned in the same position as was the previousinsert.

A clamping element 37 has an arched shape defining two feet 38 and 39,the foot 33 engaging the insert 32 and the foot 39 engaging the shank30. The two feet 38 and 39 are provided with aligned grooves 40 whichreceive aligned ridges $1 on the insert 32 and the shank 30,respectively. The clamp 37 is held resiliently downwardly by means ofthe clamp screw 42. which is threadedly received witl'L'n a suitablebore within the shank 30. The clamp 37 is held resiliently downwardlytoward the shank by means of the fastener 42 whereby the insert is evenmore precisely positioned by reason of the fact that the ridge 35thereon is even more firmly seated within the indentation 36 in theshank and more particularly within the indentation 36 in the face 31A.

It should be noted that the clamp 37 may be provided with a chip breaker45 which is fixed to the end of the clamp adjacent the bit and whichfunctions to break chips produced by the cutting operation. It shouldfurther be noted that clamp 36 is provided with an elongatedfastener-receiving slot 46 extending longitudinally of the clamp andpermitting adjustment thereof to a de sired clamping position.

Referring now to FIGS. 7 and 8, there is illustrated a furtherembodiment of the cut-off tool incorporating an alternative holderwithin the scope of the present invention. The structure of FIGS. 7 and8 comprises an elongated, slender shank 5t? and a recess 51 in thedistal end thereof, the recess having perpendicular walls 531A and 513similar to the above described cut-off tool holder. Formed within theshank is a pair of spaced parallel bores 52 and 53 which openperpendicularly upon the face 51B of the recess 51. The bores 52 and 53slidably receive in close fitting relation a pair of pins 55' and 56which are also slidably received in close fitting relation withinsimilar parallel bores 57 and 53 in bitcarrying insert 59 receivedwithin the recess 51. These pins function to align the insert 59 in theshank and to insure that each replacement for the insert 59 is in thesame position as the previous insert.

The present embodiment incorporates a similar arched clamp 66 havingfeet 61 and- 62 which respectively engage the insert and the shank. Itshould be noted that the clamp of the embodiments herein disclosed iscapable of pivoting, after release or unthreading of the fastener to aposition allowing quick and easy removal and replacement of the insert.

Referring to FIG. 9, an alternative form of cut-off tool is illustratedwhich is identical to the above described cutoff tool illustrated inFIGS. 4-6 with the following exceptions. The bit-carrying insert 79 hasits bit arranged in a somewhat different manner with respect to the bodyof the insert but more important the bottom or base 71 of the insertextends at an angle of approximately 5 degrees to the length of theshank 72. The insert has a continuous ridge 75 similar to the abovedescribed ridge 35 which extends across the base 71 of the insert andacross the face 76 thereof and is received within a complementaryindentation 77 in the two faces 30A and 80B of the recess 80.

The fact that the base 71 of the insert and the complementary face 80Bof the recess are at an angle of approximately 5 degrees to the lengthof the shank causes the insert to be more firmly seated in the recess 30because the force from the clamp 81 acts directly downwardly on theinsert (or at an angle of 90 degrees to the length of the shank) andthus firmly seats the insert against the faces 30A and 80B of the recess80 and simultanc ously firmly seats the ridge 75 in the indentation 77whereby the insert is precisely positioned within the recess.

It should be noted that while the 5 degree angle mentioned above ispreferred, it is not the only workable angle. Conceivably angles assmall as 2 degrees would produce the desired effect. The maximum anglewould appear to depend on the difiiculty of molding the shank 72(assuming it is formed of powdered metal) and also upon the possibilityof the shank cracking at the apex of the recess 86 or deformation of therecess so that the the insert would be loosely instead of firmlyreceived therein.

Referring to FIGS. lll3, a further embodiment of the cutting tool isillustrated which identical to the above described cutting toolillustrated in FIGS. 1-3a with the following exceptions. The shank S5 isformed with a recess 86 at a distal corner thereof. This recess 85,instead of being rectangular in shape has a base surface 36A which isarranged at an acute angle with the face 86B of the recess and also atan acute angle with the face 36C of the recess. In other words, theangle 87 of FIG. 13 and the angle 88 of FIG. 11 are each acute and arepreferably approximately degrees. As suggested above with regard to thecut-off tool of FIGS. 9 and 10, these angles 87 and 88 do notnecessarily have to be exactly 85 degrees even though this is apreferred value. Conceivably, these angles could be as great as 88degrees and still produce the desired effect of precisely seating theinsert 98 in the recess. The minimum value of these angles would bedetermined in like manner to that above described and would depend uponthe difficulty of molding the recess 86 in the shank.

It should be mentioned that the force of the clamp 91 acts directlydownwardly against the insert and thus, causes the insert to be forcedagainst the base surface 86A of the recess and also against the othersurfaces 85B and 86C of the recess whereby the insert is preciselypositioned. Obviously, the three faces of the insert which engage thesurfaces 36A-S6C are also arranged at the same angles as the faces86A86C. It should be noted that, when the turning tool is in operation,the clamp 91 is not needed because the work itself will tend to hold theinsert in position and against the three faces 86A- 86C.

From the above description, it will be obvious that the presentinvention provides an improved tool holder permitting quick and accuratemounting and replacement of a bit-carrying insert. It can also be seenthat the present invention also provides an improved holder for use in acut-off tool or a single point cutting tool. It can be furtherappreciated that the present invention provides an improved holder foruse with bit-carrying inserts formed from powdered metal.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiment has been shown and described and that allchanges and modifications that come within the spirit of the inventionand the scope of the claims are also desired to be protected.

The invention claimed is:

A tool holder comprising a generally rectangular shank having agenerally rectangular recess in one end thereof formed by two faces atan acute angle of approximately 85 degrees to one another, a toolcarrying insert received in said recess and having two faces mating withthe faces of said recess, said insert faces being arranged at an angleof approximately 85 degrees to one another, said insert faces having acontinuous ridge extending therealong, said recess faces having acontinuous indentation receiving said ridge, said shank and inserthaving aligned ridges, a clamp having an arched shape one foot of whichengages said insert and one foot of which engages said shank, said clamphaving indentations in the feet thereof receiving said last mentionedridges, a fastener securing said clamp to said shank, said fastenerbeing threadedly received in said shank and extending through thecentral portion of said clamp and resiliently deforming the arch of saidclamp toward said shank, the axis of said fastener being parallel to oneof said recess faces whereby the force exerted thereby is parallel tosaid one recess face and urges through said clamp, said insert againstthe two faces of said recess.

References Cited in the file of this patent UNITED STATES PATENTS1,396,180 Fors Nov. 8, 1921 1,974,215 Kilmer Sept. 18, 1934 2,181,023Moore Nov. 21, 1939 2,348,262 Oak May 9, 1944 2,595,090 Middleton Apr.29, 1952 2,675,604 Plummer Apr. 20, 1954 2,846,756 Novkov Aug. 12, 19582,883,737 Wilson Apr. 28, 1959 FOREIGN PATENTS 639,824 France Mar. 17,1928 701,534 France Jan. 12, 1929 704,143 France Feb. 17, 1931 1,105,369France June 29, 1955 1,140,048 France Feb. 25, 1957 572,403 Italy Jan.27, 1958 844,753 Great Britain Aug. 17, 1960

